1. Field of the Invention
This invention relates to intrauterine contraceptive devices and more particularly to a method and apparatus for loading the device onto the barrel of an inserter.
2. Description of the Prior Art
It has long been recognized that the presence of a foreign object in the uterus tends to prevent conception. In general, however, such devices must occupy a significant portion of the space in the uterus, and because the effective dimension of these devices is often larger than that of the nulliparous cervical canal, a dilation procedure requiring general anesthesia is often required to satisfactorily insert the devices.
In commonly assigned U.S. Pat. No. 3,777,748, the contents of which are incorporated herein by reference, an intrauterine contraceptive device is disclosed which could be conveniently emplaced without resorting to dilation of the nulliparous cervical canal. This device is known and referred to hereinafter as the "Cu-7" and it is generally in the shape of the numeral "7." It is comprised of a generally longitudinal arcuate stem member and an arcuate arm member which extends transversely from the terminal end of the stem member. The transverse arm of the Cu-7 is flexible so that it can be folded in overlying relationship with the longitudinal stem.
Conventionally, the Cu-7 device is emplaced in the uterine cavity by means of an inserter which consists of an elongated tube or barrel that is adapted to extend through the cervical opening and into the uterine cavity. The Cu-7 device is emplaced and loaded in the inserter by folding the transverse arm against the longitudinal stem, after which the end of the inserter barrel holding the Cu-7 is inserted into the uterine cavity via the vaginal and cervical openings. After the device is inserted at an appropriate depth in the uterine cavity, the device is expelled from the inserter by means of pressure exerted on its posterior portion by a forward moving piston that is disposed inside the inserter barrel. As the lateral pressure exerted on the transverse arm by the tubular inserter is released, that resilient arm springs apart from the longitudinal arm and bears firmly against the uterine wall at its terminal end while a large portion of the longitudinal arm also makes contact with the uterine walls such that the device is firmly lodged in the uterine.
It is found, however, that if the transverse end of the Cu-7 device is folded against the longitudinal arm for an extended period of time it may tend to lose some of its elasticity. It may therefore fail to regain its original "7" shape when expelled from the inserter. For this reason, it is undesirable to pre-position the Cu-7 device in its folded insertion position for an extended period of time.
Another disadvantage of the conventional devices is that the process of manually inserting the device into the canal is difficult and time consuming especially since it must be done with examination gloves so as to maintain the sterility of the device.